Exogenous melatonin-stimulated transcriptomic alterations of Davidia involucrata seedlings under drought stress

• Key message This study shows mitigating effects achieved by exogenously applied melatonin in drought-stressed Davidia involucrata seedlings and demonstrates the reprogramming of gene networks related to melatonin-mediated drought stress response. Drought stress can have adverse effects on endangered plant species such as the dove tree (Davidia involucrata Baill.). Despite significant advances in uncovering the roles of melatonin in abiotic stress tolerance, the function of melatonin in the dove tree during drought stress is unknown. Here, we show the effects of exogenously applied melatonin on drought damage to D. involucrata seedlings. Melatonin pretreatment of dove tree seedlings was correlated with reduced membrane lipid peroxidation, suppressed production of drought-induced reactive oxygen species (ROS), and improved antioxidant capacity. Comparative RNA-Seq-based transcriptome profiling was employed to dissect the mechanistic basis of melatonin in drought response. We found that melatonin pretreatment resulted in differential expression of 2737 genes (1849 up-regulated and 888 down-regulated) under drought stress. Further detailed analysis suggested that melatonin modulates D. involucrata response to drought through fine-tuning of multiple phytohormone signaling and synthesis pathways, including transcriptional stimulation of auxin signaling-related genes and brassinosteroid biosynthetic genes. Moreover, phenylpropanoid biosynthesis and glutathione metabolism pathways were activated by melatonin, which could be linked to the observed enhancement of ROS scavenging capacity in melatonin-pretreated D. involucrata seedlings under drought condition. Additionally, melatonin-mediated drought stress response may involve activation of calcium signaling via up-regulating gene expressions of CNGC, CaM/CML, and CDPK family members. Collectively, this study yields insights into transcriptionally regulatory mechanisms of melatonin action under drought stress and provides a potential strategy for ex situ cultivation and landscape application of endangered ornamental tree species particularly in the context of global climate change.

Ämnesord

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Skogsvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Forest Science (hsv//eng)

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